Modern Database Management Systems (DBMS) provide a wide range of features to support different application domains, but only a small number of applications really need all the provided features. Since the 1980s different approaches were released which introduced the development of tailor-made DBMS. They all feature either a coarse-grained modularization or focus only on the adaptability of specific features of a DBMS. Improvements in the field of software engineering, like service-oriented software development and aspect-oriented programming, are used in this thesis to develop a reference architecture for a modular DBMS. In contrast to former approaches, this approach can be considered as aModern Database Management Systems (DBMS) provide a wide range of features to support different application domains, but only a small number of applications really need all the provided features. Since the 1980s different approaches were released which introduced the development of tailor-made DBMS. They all feature either a coarse-grained modularization or focus only on the adaptability of specific features of a DBMS. Improvements in the field of software engineering, like service-oriented software development and aspect-oriented programming, are used in this thesis to develop a reference architecture for a modular DBMS. In contrast to former approaches, this approach can be considered as a kind of generic "DBMS construction kit", in which each "building block" provides its feature as a service. A tailor-made DBMS is constructed by the composition of building blocks that provide the required features. Therefore the architecture is not limited to specific extensions or adaptations, but provides a holistic approach. Additionally, to enhance the availability of the DBMS, a runtime adaptation framework is introduced to exchange these building blocks without shutting down the DBMS. Specific attention in this area is paid to enable transaction management during runtime. Furthermore a prototype is implemented in the context of this thesis. This prototype is developed on top of a service-oriented component framework, which is enhanced with respect to runtime adaptation, and used to evaluate the proposed reference architecture.…